Identification of wheels of a vehicle provides useful information on the operation or operation conditions of a road-going vehicle. For example, a tire pressure monitoring system (TPMS) for a road-going vehicle requires wheel identification means to identify the identity of each of the wheels in order to provide pressure information on each individual wheel of a vehicle.
Wheel identification means are known. For example, U.S. Pat. No. 5,600,301 has disclosed a wheel identification means in which each vehicle wheel has a transmitter with a unique code. A central receiver in the vehicle is taught, at manufacture, to recognize the codes for the respective transmitter for the vehicle. However, such an arrangement requires an application specific integrated circuit (ASIC) encoder in a transmitter which is programmed at manufacture to give individual identity to the wheel. The requirement of an ASIC to operate the arrangement has severely limited the usefulness of such a means, for example, due to the non-exchangeability of wheels among manufacturers of wheels.
U.S. Pat. No. 6,204,758 teaches a tire monitor for use in a remote tire monitor system including an accelerometer for detecting acceleration of the tire monitor as attached to the individual wheels. However, this arrangement requires the use of a radial accelerometer, a tangential accelerometer, and a YAW accelerometer in order to determine the positional information of the individual wheels.
U.S. Pat. No. 7,023,334 teaches a method for assigning tire pressure measurement devices in a motor vehicle. The method comprises determining by means of ABS when a vehicle is making a turn whether it is a left-hand or right-hand. Wheel revolution counts are then measured in each tire and sent along with identification codes to a central analysis unit. There, the wheel revolution counts are collated with the bend data determined by the ABS. The higher wheel revolution counts are then assigned to the side of the vehicle on the outside of the bend and the two lower wheel vehicle counts are assigned to the other side of the vehicle. Such a system requires an ABS unit as well as identification codes.
U.S. Pat. No. 7,010,968 has described a tire monitoring system for use in conjunction with a remote tire monitoring system of a vehicle including a dual-axis accelerometer and a control circuit. The control circuit determines position information such as the right/right position of a tire monitor on the vehicle in response to an acceleration signal from the dual-axis accelerometer. The control unit further identifies additional positional information such as front/rear position of a transmitting time monitor by detecting signal strength of signal transmission.
Known wheel identification means or arrangement is not entirely satisfactory. It is therefore desirable to provide a wheel identification means which alleviates shortcomings of known wheel identification means or at least provide an alternative wheel identification means for the choice of the public.